Circuit breakers are generally used in residential applications to provide circuit protection for low voltage distribution systems. Electrical circuits or electrical systems are protected by the circuit breakers from electrical overcurrent conditions, such as overload conditions as well as low- and high-level short circuit or fault current conditions.
Many current circuit breakers include electronic components that are generally mounted on one or more rigid printed circuit boards (also referred to as rigid circuit boards). The rigid circuit boards have a main surface that provides structural support for the electronic components and electrical connections, such as jumper wires and solder connections. The connections are useful in transmitting electrical signals from one rigid circuit board to another rigid circuit board and/or between a rigid circuit board and other electrical components. Because the main surface of the rigid circuit boards is shared by both the electronic components and the connections, space considerations on the main surface is critical for proper design and placement of the electronic components.
One problem associated with this type of rigid circuit board is that the space available for electronic components can be drastically reduced by the space requirements of the connections. For example, the width of a residential circuit breaker can be limited (e.g., a maximum width of two inches), which imposes limitations on the size of the rigid circuit boards. Another problem associated with the connections is that they require hand assembly during electronic module assembly.
Current transformers can be used in electronic circuit breakers to sense the current flowing through a wire, such as a current line. A current transformer typically includes a coil of very thin conducting wire wrapped around a core. A current line can be routed through the center of the core of a current transformer. The current through the current line routed through the core induces a current in the coil, which can be sensed. A current transformer, which includes a coil of wire and a metal core, and must accommodate an insulated conductor routed through it, can require significant space on the rigid circuit board. Moreover, because a conductor must be routed through the center of the current transformer, and the confines of the rigid circuit board are often tight, wire routing is a concern.